In daily life, people use two eyes to observe external scenery with spatial three-dimensionality. A three-dimensional (3D) display technology uses the principle of binocular stereo vision to make people acquire a three-dimensional sense of space. The main principle is to make a viewer's left eye and right eye receive different images respectively due to the positional difference caused by a distance between the two eyes of the viewer, so that two images received with “binocular parallax” constitute a pair of “stereoscopic images”. Thereby, a sense of three-dimensionality is presented to the viewer by analyzing the pair of “stereoscopic images” through the brain.